Cultivation techniques of onion with plastic film
Variety selection of 1
Generally, mid-late mature imported hybrids are selected, such as Jinshan Wang Jiu, Hongfu, Sun Green, Pandora, Audi, etc., in order to improve the commodity and output.
2 Sowing and seedling raising
Cultivating strong seedlings is the key to obtain high yield of onion. The standard of strong seedling is seedling age 50 ~ 60 d, plant height 20 ~ 30 cm, 3 leaves 1 heart to 4 leaves, pseudostem diameter 0.5~0.6 cm, and no plant diseases and insect pests. In order to cultivate healthy school-age seedlings, we can only sow them early, sooner rather than later, bigger rather than smaller.
2. 1 seedbed preparation
10 ~ 15 d before sowing, mix fertile pastoral soil and high-quality decomposed farmyard manure at a ratio of 7: 3, sieve, level and make a border, and add 100 g? M-2 is sprinkled on the bed surface. In February 10, the shed will be warmed in advance to raise the ground temperature. The seedbed area is 20 square meters per 667 square meters of field.
2.2 sowing
Sowing can be done directly in the middle and late February. In order to improve the emergence rate, it can also be scalded with warm water. Scald the seeds with warm water of 50 ~ 55℃, stir them continuously until the water temperature drops to about 30℃, then soak them for 20 ~ 30 minutes, and then take them out and sow when the seeds do not stick. If the sowing date is late, it is necessary to accelerate germination, wrap it with a wet cloth, put it at the temperature of 18 ~ 20℃, wash it with clear water 1 time every day, and sow when the seeds are 50% white. Seeding 4 ~ 5 kg per 667 m2 seedbed can colonize1.6 ~1.86hm2. Water through the bottom after sowing, and generally do not water before emergence. When the emergence rate reaches 80%, remove the plastic film according to the weather conditions and decide whether to water it.
2.3 seedling management
The principle of seedling management is to advocate controlling temperature and water in the early stage, controlling temperature and water in the later stage and strengthening ventilation. Before emergence, the temperature in the shed should be kept at 20 ~ 25℃ during the day and at 12 ~ 18℃ at night to prevent the seedlings from growing white. At seedling stage, water 1 time according to the humidity of seedbed and topdressing potassium dihydrogen phosphate to prevent weak seedlings from being formed due to fertilizer deficiency and drought. Weed manually at seedling stage 1 ~ 3 times, stop watering 7 days before planting, and increase ventilation and hardening seedlings.
3 wild colonization
3. 1 Preparation before building a group
Choose sandy loam with convenient irrigation and drainage, flat terrain, fertile and loose soil and no onion and garlic crops planted for two consecutive years, and apply high-quality decomposed farmyard manure 10 m3, plant ash 1 m3, diammonium phosphate 25-30kg, urea or long-acting ammonium bicarbonate 10-50kg and potassium sulfate 5-650. Rake the ground to make a flat bed with a width of 1.3 m, and cover it with a black or white plastic film with a width of 1.4 m and a thickness of 0.006 mm to prevent weeds from growing. Before mulching, 48% trifluoling EC can be used for closed weeding, and 30 kg (667 m2 and 25 kg) of water or sand can be added every 100 ~ 150 ml. Photolysis should be prevented in time after spraying, and plastic film should be covered before watering (7 ~ 10 d before transplanting).
3.2 Planting period and method
Generally, in late April, when the diameter of the pseudostem is 0.6~0.7 cm, the height of the seedling is about 30 cm, and the leaf 1 to 4. After emergence, dip the roots with 20% transplanting solution EC 1000 times. Eight rows of yellow-skinned onions and nine rows of red-skinned onions were transplanted, with plant spacing of 12 ~ 15 cm and row spacing of 15 ~ 16 cm, with an average of 25,000 plants planted in 667 m2 and planting depth of 2 ~ 3 cm. Seedlings should be planted straight, covered with soil after planting, and roots should be closely combined with soil. Too deep planting will affect the bulb expansion, and too shallow planting will affect the survival rate. After transplanting, water the seedlings in time.
3.3 Post-colonial management
Irrigation with slow seedling water 1 time 5-6 days after sowing, and irrigation every 10 day/time thereafter. Squatting seedlings 10 d is needed before bulb expansion, which is the turning point of onion from leaf growth to bulb expansion. Controlling watering can inhibit leaf growth and promote nutrient accumulation to the base of leaf sheath. If you don't squat, it will cause plants to grow white, which is not conducive to bulb expansion. After the bulb begins to swell, it is the key period for topdressing and irrigation. Water every 7 days 1 time, topdressing 20 kg urea, 20 kg NPK 48% compound fertilizer and 667 m2 water to meet the nutrient requirements of onion in vigorous growth period and bulb expansion period, and stop watering 7 ~ 10 days before harvesting to enrich bulb tissue and improve storage resistance.
4 timely control of pests and diseases
After transplanting, use 50% phoxim EC10 ~15kg, 600 times of 50% phoxim EC or 2.5% deltamethrin EC 1500 ~ 2000 times or 90% trichlorfon 1000 times to control underground pests. The interval between medication time and harvest period is more than 90 days. In the growth period, 800 times solution of 25% metalaxyl wettable powder, 500 times solution of 70% mancozeb wettable powder, 600 times solution of 72.2% propamocarb aqua, 50% chlorpheniramine wettable powder 1.500 times solution, 600 times solution of 75% chlorothalonil wettable powder and 5000 times solution of 64% antiviral alum wettable powder were selected. Control liriomyza huidobrensis and garlic thrips with biological pesticide 1.8% avermectin EC 3 000 times; Selecting 77% kocide wettable powder 5 00 times, 72% agricultural streptomycin wettable powder 4 000 times, 90% neophytomycin wettable powder 4 000 ~ 5 000 times and 30% DT bactericide 500 times, spraying 667 m2 solution 30 kg twice with an interval of 7 ~ 10 d to control soft rot; 300-fold solution of 6% kasugamycin wettable powder and 6 000-fold solution of potassium permanganate were selected to prevent and control nodule disease. Spraying 600 times of 50% phoxim EC or 1 500 ~ 2 000 times of 2.5% deltamethrin EC or 1 000 times of 90% trichlorfon to control ground maggots. Because onion leaves are smooth, in order to increase adhesion, 60 grams of washing powder can be added to 30 kilograms of liquid medicine.
5 timely harvest
Signs of suitable harvest time: bulbs have been fully expanded, the neck of pseudostems is soft, the tubular leaves on the ground naturally lodging, most plants' 1 ~ 2 leaves turn yellow, and the tips of 3 ~ 4 leaves turn yellow, so they can be harvested, leaving 3 ~ 5 cm pseudostems, and drying onions in the field for 2 ~ 3 d after harvesting to remove impurities such as soil. Select bulbs that are compact, free from cracking, mildew, deterioration or bolting, free from plant diseases and insect pests, and with thin skin, and then classify, bag, store, transport and sell them.
Cultivation techniques of onion with plastic film
1. Selection of fine varieties and technical treatment of seeds. Seeds are the key to increase onion production and income. There are three series of onion varieties: red onion, yellow onion and yellow onion with small hydrangea. Therefore, when selecting varieties, we should make correct and appropriate choices according to local planting habits, soil and water conditions, lighting conditions, yield indicators, disease resistance, adaptability and maturity. According to different varieties, use 200-250g seeds per mu.
Technical treatment of seeds, in order to improve the yield, and to sow the whole seedlings, seedlings together, seedlings evenly at one time, the purchased seeds should be treated scientifically and technically.
1, seeds are dried, that is, the seeds to be purchased are poured into the newspaper and dried for 2-3 days, and the seeds cannot be dried when the temperature exceeds 32 degrees.
2. Soak the seeds: blanch the dried seeds with 55-degree hot water, scrub the seeds by hand after the water temperature drops, and wash off the waxy layer of the seeds; According to the ratio of 1 kg water to 1 g nutrient chelated microelement clear liquid fertilizer, soak the seeds with 5-6 times of 30-degree warm water for 10- 12 hours, and then take out and drain the water for sowing.
Seedling raising, for onion management and yield improvement, it is best to adopt seedling raising and transplanting. Because the growth of onion seedlings is slow, the seedling stage is long, and direct seeding is not easy to manage, so seedling raising and transplanting should be carried out after September 20, and early sowing of onions is easy to bolting in the growth period, which will lead to reduced production. Nursery land should be flat, sunny, convenient transportation and fertile land. It takes 35 square meters to plant an acre of onion, and then 10- 15 kg of bio-organic fertilizer containing meat protein active bacteria is sprinkled on the nursery, turned into 5-8 cm soil, and evenly mixed to make a flat bed with a width of1m. In order to ensure that onion seedlings are neat, Miao Zhuang and uniform, straw, wheat straw and plastic are needed. If the nursery is short of water, you can use a small watering can to sprinkle water in the morning, which is beneficial to seedling emergence, and the seedling emergence time is 7- 10 days; When the onion seedlings are unearthed, the straw, wheat straw plastic film and sunshade net are gently removed, and the seedlings grow to the two-leaf stage. In order to promote the formation of strong seedlings, 300 times of total nutrient trace element fertilizer and 0/000 times of high-efficiency fungicide can be sprayed on the seedbed every ten days and a half months. Because onion seedlings grow in seasons with high temperature, large temperature difference and low humidity, the above sprinkler irrigation method can also prevent and control root rot, white rot, root rot, damping off, anthracnose, epiphyte disease and bacterial angular leaf spot, which are easy to infect onion seedlings. There are thrips on the tubular leaves of onion, which can be controlled by imidacloprid. When the young shallot grows to 3-4 tubular leaves, the young stem of the strong seedling is 0.5-0.8 cm thick, the stem base is hard, there are many fibrous roots, the leaves are dark green, and there are no pests and diseases. It can be transplanted and planted in 40-50 days.
2. Rational fertilization and scientific transplanting. Fertilizer is the basis of increasing onion production and income. Fertilizer is the treasure of crops, and it can't grow without it. A flower of a crop depends entirely on fertilizer. The unreasonable use of fertilizers leads to problems in output, insufficient use of fertilizers and discounted income. According to the national fertilizer technology policy and the principle of combined application of organic fertilizer and chemical fertilizer, the technical requirements of supplementing trace element fertilizer regularly, reasonably and continuously; Carry out the fifth rational fertilization according to one fertilization principle and two nutrient balances; Master three fertilization methods and four fertilization concepts for rational fertilization; The seventh rational fertilization adopts five fertilization indexes and six comprehensive fertilization techniques; Follow the selection measures and essentials of reasonable fertilization; Make a correct choice of the demand indexes of various crops for nitrogen, phosphorus, potassium and other fertilizers pointed out in the ninth part of rational fertilization; Onion is an underground root vegetable, which needs potassium and likes potassium. Because of the high yield, a lot of fertilizer is needed. 150-300 kg of meat protein bio-organic fertilizer and 80- 100 kg of high-potassium, famous-brand, high-quality double-chelated and double-patented potassium sulfate compound fertilizer can be used as base fertilizers per mu, which can be evenly spread and plowed for three to five times to achieve early harvest.
Scientifically transplanting and planting, onion is an overwintering crop, and the growth and development of onion bulbs need a vernalization stage, so according to the air temperature and seedling age, the transplanting and planting time of onion should be after winter 1 10. After ditching in the field, the seedbed should be watered with seedling water 2-3 days before transplanting, and then the seedlings should be raised and divided into large seedlings. Putting into the mud made of 300 times of trace element fertilizer, pulling, so that each seedling can be brought with nutrient mud as much as possible, and then planting onion seedlings on the pulled furrow back ridge in layers, wherein all the big seedlings are planted in one bed, and all the small seedlings are planted in one bed, and the plant spacing is15-18 cm; Allium wampee13-15 cm; Pearl hydrangea onion 5-8 cm; The density per mu is 1.8-2 1 ten thousand plants; 2 1-25000 strains of onion with yellow skin; There are 40,000-65,000 small pearl hydrangea shallots, and the next crop can be interplanted with other crops, depending on the situation. After onion planting is completed, enough planting water can be poured into the small ridge, and the water surface needs to be flooded over the small ridge where onion is planted. After watering the planting water, apply 1 kg nutrient chelated microelement clear liquid fertilizer per mu, which is beneficial to onion rooting, anti-freezing, cold prevention, drought prevention and early turning green in spring. After water seepage, the special herbicide for onion field should be applied. Covered with silver-gray plastic film, and pressed with soil around and in the middle to avoid the wind blowing the plastic film in winter, which can not achieve the heat preservation effect and is not conducive to onion rooting in winter.
Third, onion field management, management is the guarantee of increasing onion production and income. In winter, the temperature is low and there is much snowfall. Onions are insulated and protected against freezing under plastic film, which is beneficial to vernalization stage, promoting root development and improving the ability of absorbing nutrients in early spring. It's beginning of spring season on February 5th. We should pull the onion seedlings out from the plastic film and spray them on the leaves once a month with 150 times of total nutrient micro-fertilizer and 1000 times of high-efficiency bactericide to prevent and treat diseases and grow sturdily. At the same time, 20 kilograms of quick-acting compound fertilizer should be watered with green water. If you want to harvest onions in advance and sell them at a good price, you can also add a small arch shed and cover 4-5 rows of onion seedlings with it. The method is to use a bamboo pole with a width of 4 cm and a length of 1.8-2 m, cut the root by 50 cm, wrap it with a plastic rope in the middle, and then use polyethylene to prevent dripping.
Onion 6 leaves 1 core enters the vigorous growth period, and 8-9 leaves enter the bulb expansion period, so the demand for onion fertilizer is at its peak from the 6-leaf stage, and not only nitrogen, phosphorus and potassium fertilizers, but also medium and trace element fertilizers are urgently needed. Therefore, the land should be watered when it is wet and dry, and the yield of onions should not be affected by drought. Because onion likes humidity but is not drought-tolerant, when watering for the second time in spring, that is, after the sixth leaf stage, clear liquid fertilizer of 1 kg total nutrients and trace elements should be applied again, biogas slurry can be washed for the third time conditionally, high potassium and quick-acting compound fertilizer can be washed again unconditionally, and clear water can be poured for the fourth time; On March 25, the vernal equinox has passed, the weather is getting warmer, and the small arch shed is going to be demolished. In addition, March-April is also the key period of purple spot, downy mildew, leaf mold, gray mold, epiphyte, stem rot and bacterial angular spot of onion during the onion flourishing period due to the abundant spring breeze, little rainfall, large temperature difference, high air temperature and low ground temperature. Please use 500 times efficient bactericide and prepare special bactericide 800- 10 in time. Onions are tubular leaves, so spraying pesticides can't keep water. Pesticide synergist should be prepared to prevent the liquid from flowing downwards, because the disease spreads quickly at this time, and the onions in the field will be destroyed if you don't pay attention for a few days. Therefore, we must raise awareness of disease prevention and treatment and implement the Ministry of Agriculture? Prevention first, comprehensive prevention and control? Plant protection policy. It is better to treat a disease than to prevent it early; Good prevention and cure, not prevention and cure; Focus on prevention and treatment; Control effect increases yield and control effect decreases harvest. At this time, onion thrips are also the main obstacle to onion growth and yield, so imidacloprid and acetamiprid should be used in time for control. There are also underground onion maggots, meadow moths and needle worms that also take the opportunity to harm our onion roots. We need to use pesticides such as emamectin benzoate or avermectin benzoate to control pests and diseases when watering, so as to control pests and diseases, increase nutrition and create good conditions for onion bulb expansion. The output of onions is in jeopardy.